She's dead, Jim: 2600 Comp. Mod, PLEASE Help!

[AtariKari]

Hi -

 

I was bound to happen. I took a stab at the 2600 Composite Video Mod, using the instructions from the "How To" section on this site. *ahem* This is my first soldering project. *ahem*

Ever.

 

Below gets a bit garbled, I'd say techy but I'm not quite sure I know what I'm talking about...

 

PROBLEM: Upon completion of the mod, I can get a slowly _rolling_ video signal, but only for a split second when I flip the TV into Alt. Input Mode. Then it cuts to "Unusable Signal," no video, and stays that way indefinitely. I am quite proud that anything works, but obviously I am a little short of a working system. This is my only 2600 and I have just purchased a Cuttle Cart. Below is a little drawn out and long, but I am trying to be as meticulous as possible. Please help!

 

On my system, in the R41 (Chroma) location, the bands are actually colored: Gold, Red, Orange, Orange (bottom to top) on my system, but the piece itself (a transistor (?) is in the right place on the circuitboard.

 

The "Gold/Red/Grey/Blue" transistor from the "How To" guide is actually located adjacent to C19, on the right-hand side of TP5.

 

-question- is it the color, or the location of the piece that determines which one to solder the jumper to from TP5? I'm pretty sure it is the latter, but am trying to find anything to troubleshoot on...

 

My soldering job is not so great, so TP5 has a big blob over it.

 

-question- How precise need one be? There is no solder from TP5 that touches any other wires; though it does bleed over to touch the adjacent transistor (R42).

 

-question- Does R41 have a line on the circuit board that connects it to the transistor directly below it? I dropped too much solder there, and can't remember if it was the case before. Clearing away the excess solder, it does look like there is a pre-formed line downward, but I'm unsure...

 

-question- does the quality of the jumper cable play a huge role in signal quality? I literally used a piece of wire I found around the house.

 

-final question- What is causing the video roll, then sudden cut of video signal?! The only way I can get the signal to return is to flip from TV "AUX" mode to "regular" then back again. This only returns the signal for a split second, then it dies again.

 

PLEASE help! I'm going to Radio Shack as soon as I get several responses from you guys. A desolderer is already on my list...

 

thanks so much in advance, if I can get this to work it would make the weekend!

[+RangerG]

Best of luck Mike -- my Christmas break from graduate school starts in a week and a half and I want to try the mod myself when I have the time. However, I am quite the newbie at electronics. Your success will spur me on (or vice-versa . Again - really hope you get it worked out.

[AtariKari]

RangerG -

 

Hey, thanks man! I've learned a lot about the process of soldering / desoldering in the past few hours, but my failure to get a constant video is disheartening. When I get this puppy up and running, I'll provide you with any tech help required!

 

I'll keep you posted. Hopefull...

[Paul Slocum]

Have you tried hooking it up to a different TV or monitor? I've read that some TV/monitors won't work as well with the mod.

 

-Paul

[AtariKari]

I just redid the soldering. Cleaned up the contacts, respliced the wires. Same result

I tried through a different TV, no help. Will give it a shot with a third TV soon. I am using a new 27" RCA with A/V inputs in the back, BTW. I checked the inputs with a Jaguar earlier and they work fine.

 

Could I have melted something beyond repair and not know it? The resistors have taken a little heat, but not so much that I have melted through...The main symptom, I think, has something to do with the rolling screen, and the brevity of its display. If someone would give a hypothesis as to what / where this fault may lie, it would help greatly. The signal I do get is great, but it doesn't last.

 

I have purchased some new 22 Ohm resistors and a few pots, and will now try Heckerdorn's variation on the hack...wish me luck, I'd settle for blind luck if I can get it.

[+Mitch]

Ugh, I don't like that mod. The reason it's not working is because the video signal from the 2600 is not strong enough to drive the TV. As a quick fix you can try running it through a video amplifier (sometimes a VCR will work).

 

Mitch

http://atari7800.atari.org

[Sylentwulf]

SAME thing happened to me, it looked and sounded GREAT, but it was "rolling" looks like a PAL cart or the wrong channel or something, I ended up giving up. desoldered it, and then I lost sound when I did that (probly due to my horrible DEsoldering). I gave up and just used the "radio shack adapter" which I now sell on ebay heheh.

[+RangerG]

Mike -- any luck? Did you follow written instructions or see pictures. This site has nice pictures of the mod:

http://www.classicgaming.com/vcsp/HowToMAIN.htm

 

Keep us informed and best of luck -- I know things can get frustrating! -- Randy

[AtariKari]

Hey all -

 

First off, it is very reassuring to get so much feedback as I blunder my way through this. Thank you. The 2600 community is far more cooperative and supportive than, say, the Jaguar group. Its a sad thing to see message boards like JI (JI) turn from a community to the standard shouting match. Many publishers/developers don't get the respect and support they deserve there. But I digress...

 

I thought at first that the sync problem (if that is indeed whats wrong) was caused by my having a new TV that refreshed at a higher rate than the 2600 was spitting out. Several of your posts indicate that I may have to boost the signal strength, so I'm going to err on the side of optimism and blame that.

 

I'll be going to Radio Shack again after work to get the required pots for the Heckerdorn hack (B. Heckerdorn, save me now!. Thanks for the link, RangerG. I hoped to get this done earlier today, but bought the wrong pots. It is amazing what you can forget on a short subway ride into the city...

 

The main question I have now is whether or not this hack works with any digree of success. How much success has anyone had with this one?

Does it end up boosting the signal, or do I need to eventually do the other hack for that, given that I have no VCR?

 

The 2600 truly is a tank, BTW. I have had much fun failing at this over and over again, thanks to such a resilient construction, I can only assume. Once I finally get this to work, I'll help anyone else along that needs it.

[Alex]

A number of people have noted problems with the mod on this site. Apparently it is the result of a weak video signal. I've done this exact mod before and it worked, but tried it recently on another unit and I got a weak video signal.

 

In any event, if anyone wants to write a better mod tutorial, we would be happy to replace the current page on this site. I would do it myself but particularly gifted in this area and surely someone else could do a better job. We can take care of all the posting and page coding, if someone can provide good instructions and pictures.

[jsoper]

I agree with Mitch, and in fact I don't like Heckendorn's mod either. You need to get a transistor in there to act as a buffer, a 2600 is too wimpy to drive 75 ohms.

 

My advice is:

 

1. Do the chroma luma mod in the FAQ. If you only want composite, use just one transistor for everything. A 2600 chroma/luma setup on a 1702 looks incredible though; it's worth the extra effort.

 

2. First put your circuit into a protoboard (a plug-in board that Radio Shack sells) and verify before you solder components together (still gotta solder wires)

 

3. Start with just VCC,GND,SYNC, and one LUM line. This should give you a picture, then add the other LUM's, chroma, and sound

 

4. Keep checking your RF output as you do things, it should keep working

 

5. Keep wires short, I like to clip resistors down to almost nothing and solder them standing up on the motherboard. Shorter connections = sharper video edges.

 

6. If you're bad at soldering, take the three 2600 IC's out of the sockets first. Don't keep the heat on for a long time, soldering should be quick. Put solder on the board and component separately first, then they join fast.

 

7. Or just get all the components and instructions and take it to a small TV/VCR repair place and ask if they'll do it. (Has anyone tried this? I wonder what they would charge?).

 

8. (almost forgot) The LUMA lines are swapped in some mods and schematics. Just connect resistors in the same order as the ones already on the board (smallest to largest resistance)

 

9. Remember to have fun. Lots of people enjoy working with their hands.

 

John

[+RangerG]

I for one really want to do the mod, but I would need paint by number instructions with pictures . Maybe the tv/repair shop idea isn't so bad. Mike -- any success?

[AtariKari]

You know I've considered the TV repair option, but I'm really having fun working (read wrecking) on the mod myself. That may change if I can't get any progress within the next few days, however.

So I'll be stopping by Radio Shack again tonight, and would appreciate a list of what I'll need. -pause to take phone call- I just got a new job! WOOHOO! I've been working on this for weeks; WOO HOO!

Ahem. *cough* Notwithstanding that I will most likely drink myself into a coma tonight (why do we tend towards destruction in moments of triumph? Entropy?), I'll get the parts and maybe give the Heckerdorn hack a shot soon...The big question, John, et. all, is will this one have a better shot of working? Do I need to add any parts in addition to those on his site?

Also, I am devoid of any electronicspeak capacity, so please clarify the following. All apologies for requesting to be walked through so slowly, and all appreciation in advance:

-----cut from John's mssg-----

1. Do the chroma luma mod in the FAQ. If you only want composite, use just one transistor for everything.

-where do I place said transistor? Both Heckerdorn's faq and the Atari Age one don't list one in the parts list.

 

2. First put your circuit into a protoboard (a plug-in board that Radio Shack sells)

-how? what parts to attach here? should Radio Shack guys be able to guide me through this? What size to fit it back in to the 2600 casing?

 

and verify before you solder components together (still gotta solder wires)

-again, how?

3. Start with just VCC,GND,SYNC, and one LUM line. This should give you a picture, then add the other LUM's, chroma, and sound

-this is off the Heckerdorn hack, yes?

 

I'm assuming you'd suggest I move slowly and test the signal as I go, using Heckerdorn's hack. The transistor suggestion just threw me, as well as the breadboard idea (though I know what a breadboard is, I'm not sure what to do with it).

 

Thanks again, man this is fun!

[+RangerG]

Mike -- post if it you get it working. Maybe you can make your own guide for extreme newbies . I used to solder some when I built radio control cars, but that was a good 15 years ago. Working with your hands is fun (especially as a break from graduate school) -- I want to try over Christmas break. Enjoy!

[jsoper]

First of all, congrats on the job!

 

To clarify, there are at least three different 2600 video mods:

 

1. How-to Page -- no extra components used

2. Heckendorn mod -- uses resistors and pots

3. 2600 FAQ chroma luma mod -- uses transistors, caps, resistors, diodes and 4050 IC (last one optional)

 

I don't think 1 and 2 work that well. If you want to do one of them go ahead.

 

The info below is only for #3

a. This works well because the transistors are set up as current amplifiers with a gain of about 10. The 2600 only has to drive a (roughly) 750 ohm load instead of a 75 ohm load (standard TV)

 

b. The chroma luma mod uses two transistors, but if you only want composite, just connect the 6.8k resistor to the base of the first transistor (where all those other resistors connect into) instead of to the base of the second transistor. You don't need the second transistor at all.

 

c. There is no parts list, just write down what you need from the schematic.

 

d. You can solder the components together onto a breadboard, or you can stuff them into a protoboard. Radio Shack sells them for about $20 (there's only one size).

 

e. The good thing about a protoboard is that you can move components around to fix mistakes (the luma resistors always seem to get in the wrong order). It's easier than soldering a component, then unsoldering it, then soldering it somewhere else. Less chance of damaging things with heat also.

 

f. Even with a protoboard, you still have to solder connection wires onto the 2600 board in 8 places: 5v, gnd, sync, lum1, lum2, lum3, chroma, audio. You might be able to use small alligator clips for some of these.

 

g. One you get a protoboard working, you can solder the components onto a breadboard (and use the protoboard for future projects) or keep them on the protoboard (I'm pretty sure it will fit in a 4 or 6 switcher). If you're going to solder, put the transistor on last. It's is the easiest to damage with heat.

 

h. If you're still lost, poke around a 2600 board with an ohmmeter while looking at Dan Boris's schematics: http://www.atarihq.com/danb/

Check whether things make sense to you. Do you read 0 ohms between TIA pins 12 and 13?

 

i. I'd vote to keep the protoboard for other projects. That chroma luma transistor circuit will work for a 5200 and 7800 with a few changes. With other changes it will give composite video on intv's and colecovisions. I don't have a single RF system anymore

John

[AtariKari]

Thanks! This job is a big break for me, and in this city those seem to be rare indeed...

 

*gulp*

O...K. I've printed out several pages of schematics, etc. and will run screaming to some poor Radio Shack guy soon enough. I can see it now:

 

"Hi, I'm working on my first soldering project. I think this is called a schematic. Help me."

 

"Couldn't I just sell you a phone? It'd be much easier."

 

"I don't mind-I'll work hard."

 

"I wasn't talking about you."

 

Or something like that. I'll keep you guys posted. BTW, I am working on a Junior Model, so stuffing an extra board in there is not an option. Besides, how will I save space to nail a Cuttle Cart dedicated CD player on top when I'm done with this?

 

I'll write some type of "Help Me, Too" file when I finish this. First, I'll give mod #2 a shot, likely tonight. The third looks so daunting I'd rather exhaust all options first.

 

Hopefull,

[liveinabin]

right, spanner in works - will this work the same for a PAL 2600?

[AtariKari]

Which one is "spanner in"? Seriously.

[liveinabin]

hehe. but really, does anyone know if it makes any difference to this mod whether your atari is PAL or NTSC?

I have no idea, I know that electric things flow through it, but after that it might as well be being carried by tiny pixies.